Last year two students of the Van Hall Institute published a study, commissioned by the European Zoo Nutrition Centre, on the dietary requirements of Orlitia borneensis, Heosemys grandis and Siebenrockiella crassicollis. Some day in the future the entire study will be available for download on the EZNC website. Till then, the recommended diets are listed here:http://www.heosemys.org/dietaryrequirements.php
I have omitted details so as not to cross the line between quoting and copying.
As usual, any comments are welcome.

For my girls i have been using a 30% proteins (fish,chicken,cricket,worms), 30% dark greens(collards,turnips,kale,mustard),30% fruits (banana, strawberry, melons,apples,oranges) and 10% prepared reptile foods and some live fish. Is this Too far off? They are extremely healthy and have had no health issues to date. I also use the dusts for my greens once a week. Should i switch over to the feeding chart mentioned or should i keep too what has been good thus far? thank you for your thoughts. Turtle man dan. Its a name that has stuck since highschool, darn ninja turtles.

People who are new to turtles, and who are at a loss about what to feed them, should use the recommended diet. That diet is exactly right - it contains all the nutrients in exactly the right amounts. But if you have some experience, then you can stick with what works best for you. There is more than one good way to take care of grandises
Just make sure you remove the seeds from the apples and other fruits before you feed them. Fruit seeds can be toxic to turtles:viewtopic.php?f=3&t=29&p=71&hilit=apple%20seeds#p71